Electromagnet and solenoid.



A. SIMON.

ELECTROMAGNET AND'SOLENOID.

APPLICATION FILED JUNE 6, I910. RENEWED OCT. 10,1913.

1,142,852. Patented June 15 1915.

UNITED STATES PATENT OFFICE.

ARTHUIL SIMON, OF'MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER-HAMMER MFG. (30., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

ELECTBOMAGNET AND SOLENOID.

Specification of Letters Patent. Patented June 15, 1915.

Application filed June 6, 1910, Serial No. 565,21 1. Renewed October 10, 1913. Serial No. 794,517.

To all whom it may concern: 1

Be it known that I, ARTHUR SIMON, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Electromagnets and Solenoids, of which the following is a full, clear, concise, and exact description, reference being had to the accompanyin drawing, forming a part of this specification. I

My invention relates to improvements in electromagnets, or solenoids.

1 It is the principal object of my: invention to provide an electromagnet, or solenoid which will automatically reduce theamount of current flowing through its energizingwinding after the same has responded, but not until the plunger, or movable armature thereof, has reached the full limit of its stroke. I

Various other objects and advantages of my invention will hereinafter beclearlyand fully set forth.-

In order to more fully disclose the nature and characteristic features of my invention, I shall describe the device illustrated in the accompanying drawing which embodies my invention in one form. It should be understood, however, that my invention is susceptible of various modifications and is not limited to the particular embodiment there of illustrated in the drawing.

In the accompanying drawing, Figure 1 illustrates a sdlenoid operated switch embodying my invention in its preferred form, the solenoid winding and the stationary plug thereof.being shown in section, and Fig. 2 is a view of the auxiliary switch its cooperating contacts illustrating a modification or my invention.

The device illustrated in Fig. 1 comprises essentially a magnet frame 8, in which is mounted an electromagnetic winding 4. Within the winding 4: is arranged a longitudinal plunger 5 arranged to engage and seal with a stationary plug 6 suitably sccured to the magnet frame and projecting into the upper end of the solenoid winding. Of course, the solenoids may be used for various different purposes As illustrated, the plunger thereof is provided with a tail tionary contacts 1st and 15 and is normally' ,held in' engagementtherewith by the coil spring 16 surrounding the stem 13 thereof, and bearing against the stationary plug 6. Inthe present instance, the auxiliary switch is arranged to control a resistance 18, which "is short-circuited thereby when said auxiliary switch engages its stationary contacts.

Before describing the operation and functions of the switch illustrated in the drawing, I desire to briefly discuss the conditions existing in the switch heretofore designed to automatically reduce the amount of current flowing through the same. Where it has been desired to accomplish this result, it has been customary to provide a solenoid with an auxiliary switch arranged to control a resistance similar to the resistance 18 which, as will hereinafter be described, is arranged to be connected in series with the solenoid winding. Heretofore, however, it has been customary to operate the auxiliary switch mechanically as the plunger of the solenoid approaches the limit of its movement. Ordinarily the auxiliary switch has been arranged to be operated by the plunger itself. Thus in order to secure operation of the auxiliary switch it has been necessary to so adjust the same that it will be operatedjust prior to the sealing of the plunger with the stationary plug. Hence, the protective resistance has necessarily been inserted in circuit with the solenoid winding before its plunger has actually sealed with the stationary core. Ordinarily the protective resistance is only required where over excitation is required to operate the solenoid plunger owing to its load. Hence, if the protecting resistance is inserted in series with the solenoid winding before the plunger has firmly sealed with the stationary plug, either the plunger will not be attracted to the full extent of its movement,

or else it will only be finally sealed with the stationary plug after objectionable vibrating, or telegraphing thereof. This vibrating, or telegraphing is due to the premature 5 reduction in the magnetic attraction by the insertion. of the protective resistance.

It is to avoid the decrease of the magnetic pull of the solenoid, before the plunger is moved to its full extent, that my invention is particularly aimed. I shall now describe the operation of the switch illustrated in the drawing to show that the same will accomplish this result. 1 v

Let it be assumed that current is supplied to the solenoid winding 4 from supply lines 20 and 21, the circuit of said solenoid winding being controlled at will by a control switch 21 With the parts in the position illustrated, upon closure of switch 21. the

5 circuit is closed as follows: From main line 20, through switch 2?, by conductor 22, through. auxiliary switch 12, by conductor 23, through the solenoid winding l, to conductor 21. The solenoid winding is thereupon energized tending to draw its plunger upwardly. The spring 16 is so adjusted as to prevent the magnetic attractionof the auxiliary switch until the sol noid plunger 5 has sealed with the stationary plug T is is hy fact that dun ing the movement of the solenoid plunger, current and consequently the magnetism is malntained below normal value due to strength ger seals with the stationary core. While the magnetism. of the solenoid remains below normal, only a comparatively few magnetic lines of force stray through the stem of the auxiliary switch with the result that the spring 16 will overcome the slight magnetic pull thus exerted upon the auxiliary switch When, however, the plunger seals with the stationary plug the current and the magnetism rise to the maximum strength. thereby saturating the plug with magnetic pines of force, a suflicient number of said ines of force now passing through the stern of the auxiliary switch to attract the same against the opposition of the spring 16.,

' other words, the stem of the auxiliary switch in efi'ect forms an auxiliary plunger for the solenoid winding,'which owing to the an rangement thereof in the stationary plug and further owing to the resistance of the spring 16, will not be attracted until the main plunger has been moved to its full extent, thereby sealing with the stationary plug 6. As soon as the auxiliary switch l2 is drawn away from its stationary contacts, the protective resistance 18 is inserted in se ries with the solenoid winding, thereby reducing the flow of current through said winding to a safe value. However, even with the resistance iii in circuit a suficient Secondly, the coils 25 and 26 self-inductance and only amount of current is allowed to pass through the solenoid winding to maintain the plunger 5 in raised position. lhe auxiliary switch will be maintained in its re tracted position until the solenoid winding is deenergized, whereupon the spring 16 will again move the same into engagement with its stationary contacts.

In Fig. 2, the stationary contact of the auxiliary switch is connected to conductor 22, through a coil surrounding said contact. Likewise the contact 14L of the auxiliary switch is connected to conductor 23, through a coil 26 similar to the coil 25. The coils 25 and 26 perform a twofold function. In the first place, they create a magnetic flux which tends to magnetically hold the auxiliary switch 12 in engagement with the contacts i l and 15. @f course, this magnetic attraction of the auxiliary switch opposes the pull of the solenoid winding 4; and, therefore, must be taken into account in adjusting the spring 16, to insure the magnetic attraction of the solenoid i overcoming the combined opposition of the spring and the magnetic attraction of the coils 25 and 26, at the proper time. The auxiliary switch heing magnetically attracted to the contacts 14 and it will, when finally attracted by the ing' leave contacts with a snap action, thereby giving a quick break of the short-circuit around the resistance 18. will create a magnetic flux which will extingush any arcs drawn ruxiliary switch and stationary contacts upon separation thereof.

As before set forth, my invention is susceptible to various modifications and, therefore, the structure illustrated and heretofore described should not be considered as limiting the scope of my invention.

Having thus described my invention, what. I claim as new and desire to secure by Let ters l atent, is:

l. A solenoid having a main plunger and an auxiliary plunger, the latter being attracted only after a predetermined movement of the former and controlling means for said solenoid actuated by said auxiliary plunger,

2H V 5! having a stationary pole piece a movable magnetically attracted part adapted to seal with said pole piece, of a switch having a magnetic portion projecting into said pole piece and arranged to he electromagnetically moved to operate said switch to reduce the ilow of current through electromagnet, and means for preventing operation of said auxiliary switch until said movable magnetically attracted part has sealed with said pole piece. l

3. The combination with a solenoid having a stationary core anda movable plunger arranged to seal with said core, of an auxiline combination with electromagnet.

iary switch having a magnetic portion projecting into said core and forming an auxiliary plunger for said solenoid, said auxiliary plunger being adapted to be attracted after said first mentioned plunger has sealed with said stationary core to operate said switch to reduce the flow of current through the solenoid winding.

4;. The combination with a solenoid having a stationary core and movable plunger arranged to seal with said core, of a switch having a magnetic portion projecting into said core and formin an auxiliary plunger for said solenoid, sai switch being adapted when operated to reduce the flow of current through the solenoid winding, and means for preventing the attraction of said switch until said plunger has sealed with said stationary core.

5. The combination with a solenoid having a stationary core and movable plunger arranged to seal with said core, of a switch having a magnetic portion projecting into said core and formin an auxiliary plunger for said solenoid, said switch being adapted when operated to reduce the flow of current through the solenoid winding, and a spring interposed between said switch and sai stationary core for preventing the attraction thereof by said solenoid until said plunger has sealed with said stationary core.

6. The combination with an electromagnet having a movably magnetically attracted part, of a switch adapted to be magnetically attracted by said magnet to reduce the flow of current therefrom after the movable magnetic-ally attracted part has reached the full limit of its movement, an electromagnetic means tending to hold said switch in engagement with its stationary contacts.

7. The combination with an electromagnet having a movable magnetically attracted part, of a switch adapted to be magnetically attracted by said magnet to reduce the flow of current therethrough, after the movable magnetically attracted part has reached the full limit of its movement, and electromagnetic windings provided with pole pieces forming the stationary contacts of said switch. In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

ARTHUR SIMON.

Witnesses:

FRANK H. HUBBARD, GEORGE HAYNES. 

